176. The Nobel Prize in chemistry was awarded to three scientists for their discovery that plastic can be made electrically conductive—an advance that has led to improvements in film, television screens, and windows.

A. that plastic can be made electrically conductive—an advance that has led

B. that plastic can be made electrically conductive—this advance leading

C. that plastic can be made to be electrically conductive, and this advance led

D. of plastic's ability to be made electrically conductive, with this advance leading

E. of plastic being able to be made electrically conductive—an advance that has led

A: correct, discovery后直接跟that从句,排除D,E; 用that从句修饰an advance是同位语的首选

B: 同上

C: be made to be错

D: 应为that从句

E: 应为that从句

这道题A和B两个选项中A的that修饰advance是更好一些, 但我不明白的是为什么要用has led呢?

"discovery"虽是过去某一时刻发生的,但对现在存在持续的影响,故用现

在完成时.